megacephaly vs macrocephaly

megacephaly and macrocephaly both are nouns.

Word	Noun	Adjective	Verb	Adverb
megacephaly	Yes	No	No	No
macrocephaly	Yes	No	No	No

As nouns, megacephaly and macrocephaly are synonyms defined as:

megacephaly and macrocephaly: an abnormally large head; differs from hydrocephalus because there is no increased intracranial pressure and the overgrowth is symmetrical

Other synonyms of megacephaly include megalocephaly.

megacephaly (noun)	macrocephaly (noun)
an abnormally large head; differs from hydrocephalus because there is no increased intracranial pressure and the overgrowth is symmetrical	an abnormally large head; differs from hydrocephalus because there is no increased intracranial pressure and the overgrowth is symmetrical